Hi, On Thu, 26 Jun 2003, Kai Schaetzl wrote:
> Tony Earnshaw wrote on Thu, 26 Jun 2003 15:34:17 +0200: > > > I, and many other (increasingly many other) mailadmins refuse on invalid > > HELO/EHLO credentials. Many can not afford to, many see this as a main > > weapon against non-ham. > > Well, what do you exactly do to refuse them? Do a reverse lookup and see if > it matches? Isn't that quite rigid and will also reject legitimate mail in > maybe 10% of all instances? HELO/EHLO credentials don't have to match an existing host name but they do have to be formatted properly (i.e. FQDN) I reject on broken HELO format with Postfix using: smtpd_helo_required = yes smtpd_helo_restrictions = permit_mynetworks, hash:$config_directory/moron_bypass, reject_invalid_hostname, reject_non_fqdn_hostname, reject_unknown_hostname, hash:$config_directory/ffd_source, permit reject_invalid_hostname drops connections with broken hostname syntax reject_non_fqdn_hostname rejects connections with HELO not formed as a FQDN reject_unknown_hostname drops connections from machines without DNS A or MX record (twitchy) hash:$config_directory/ffd_source ostensibly does some sanity checks on mail purporting to come from freemail services (a hack I picked up on SPAM-L) and hash:$config_directory/moron_bypass allegedly whitelists connections from borked-but-borked servers. I'm not sure if it works. I wouldn't recommend some of these options for most installations. I get FPs, especially because of reject_unknown_hostname, causing me to temporarily lift that restriction every week or so (I suspect moron_bypass is not working...) FPs are nowhere near 10% (much, much less) and this blocks a fair chunk of spam. YMMV. hth, -- Bob ------------------------------------------------------- This SF.Net email is sponsored by: INetU Attention Web Developers & Consultants: Become An INetU Hosting Partner. Refer Dedicated Servers. We Manage Them. You Get 10% Monthly Commission! INetU Dedicated Managed Hosting http://www.inetu.net/partner/index.php _______________________________________________ Spamassassin-talk mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/spamassassin-talk
